I found my time at the saleyards in Gloucester a bit confronting when I went with a friend earlier this year to sell two of her horses (she took both of them home again and one has since been sold privately).
I did see alot of different horses of all shapes, colours and sizes though. There were over 60 horses in the ring auction which took a good few hours. Owners led or rode their horses in and told the announcer horses age etc and starting price and the bids began until sold or handed in. Highest price the day I went was (I think) $1200 for a reining trained gelding and lowest was a couple of hundred for an aged pony. Personally I would want to know alot more about a horse than 5 minutes in a saleyard can tell.
Oh there was a non-riding horse (doggers) auction earlier in the day but these horses were gone by lunchtime. I tried not to look in that direction cause I find it so sad. If you can give one another chance - good for you - just remember that a horse lives a long time.
May I suggest OP rescues a horse that has been assessed and trained as a suitable mount? Or as mentioned above you could look into rehoming a brumby? And yeah, it's ALOT of commitment keeping a horse but so very rewarding.